Over the years on Don't Be Tardy, we've watched Kim Zolciak-Biermann's daughters Brielle and Ariana Biermann grow from little girls into young women. But growing up in the spotlight hasn't always been easy for the girls. In a new interview, Kim just opened up about Ariana's "heartbreaking" struggle with body image.

Kim shared that her 17-year-old daughter experiences body shaming in the form of "nasty comments" on Instagram: They say "'you're fat, you've always been fat...' Just horrible, mean, mean things," The Real Housewives of Atlanta alum told ET. "It’s a constant battle." and I always want my girls to love themselves, no matter what size they are."

But the high schooler has tried to channel the negativity into something positive: a new commitment to fitness. "[Ariana] works out at the gym every day," Kim revealed. "She’s really kind of come into her own."

And, as a result of all her hard work, "Ariana, now, she's lost like 30 lbs," Kim shared. "She's itty-bitty tiny."

Though being healthy is always a good thing, Kim wants "my girls to love themselves, no matter what size they are." She continued, "I am not open to any plastic surgery on my girls at this time. I tell them, you know, when you’re done having kids and all that good stuff, worry about all that stuff later on down the road, if that’s what you want to do, but you guys are beautiful and so young."

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